1. Field of the Invention
The invention relates to a strut-type suspension device for a vehicle.
2. Description of Related Art
A strut-type suspension device in which a shock absorber also serves as a suspension support is known as one suspension device. The strut-type suspension device has a structure in which an upper end side of the shock absorber (strut) is mounted to a vehicle body side via a supporting member such as an upper support, and a lower end side of the shock absorber (strut) is mounted to a wheel side via a connecting member.
In the strut-type suspension device, a coil spring is arranged surrounding the shock absorber. A lower end of the coil spring is supported by a lower spring seat that is fixed to a body of the shock absorber, and an upper end of the coil spring is supported by an upper spring seat. The upper spring seat is rotatably supported by the upper support via a bearing.
The bearing is typically arranged orthogonal to a shock absorber axis (strut axis), with the bearing rotational axis aligned with the strut axis. Therefore, the upper spring seat rotates around the bearing rotational axis, while the lower spring seat rotates around a king pin axis. When the upper spring seat and the lower spring seat rotate simultaneously, a rotational moment is generated around the king pin axis, and as a result, the ability to travel in a straight line is impaired.
Japanese Patent Application Publication No. 2002-283820 (JP 2002-283820 A) describes a strut-type suspension device that aligns a king pin axis with a bearing rotational axis by mounting a bearing and an upper spring seat at an angle to a lower portion of an upper support via an angle adjustment member. Similarly, U.S. Pat. No. 5,454,585 describes a strut-type suspension device in which a circular flange member is interposed between an upper support and a bearing, to align a king pin axis with a bearing rotational axis.
With both JP 2002-283820 A and U.S. Pat. No. 5,454,585, an inclined member that is inclined is interposed between the upper support and the bearing in order to align the king pin axis with the bearing rotational axis. Using this inclined member leads to an increase in the number of parts, and cost and weight due to using the inclined member increase, which is undesirable. Moreover, in the assembly process of the suspension device, the inclined member must be properly assembled in a predetermined position in order to align the king pin axis with the bearing rotational axis, so assembly work is not easy.